The advancement of information technology allows the creation of smart devices that not only are programable, but also can perform machine-to-machine communication in order to reach a flexible large-scale manufacturing strategy in Industry 4.0. However, as more components are connected to the Internet, cyber-criminals can perform malicious actions remotely. As one lasting threat, sabotaging smart devices' execution integrity can cause a large financial loss, i.e., causing malfunctioning. Hence, it is important to secure the execution integrity of smart devices in Industry 4.0. Motivated by the emerging blockchain technology, in this paper, we focus on how blockchain can help Industry 4.0 application protect execution integrity and propose a blockchainbased execution protection scheme named NoSneaky, which is low-cost and can be easily integrated into the current production systems. In the evaluation, we demonstrate its performance and effectiveness in securing the execution integrity.